LCD 10" UP/DN - R/L seem don't work

[essebie]

Hi at all,

I'm trying the LCD 10" TS, it's a 12 o'clock viewing angle, while for the front view it would need be at 6 o'clock.

I have tried to flip the image shorting the jumpers on R24 or R31 but nothing happens, contrary to what is written on the datasheet.

There may be another way to rotate the image 180°, perhaps using the settings on file .fex?

Thank in advance for an answer.

Stefano

[essebie]

> There may be another way to rotate the image 180°, perhaps using the settings on file .fex?

I have verified that is possible rotate the framebuffer, so I think the problem is fixable in this way.

Stefano

[granite_crusher]

It is so because LCD panels (look to schematics) have pins of lines U/D L/R is disconnected from GPIO with open jumpers, and instead one line is connected to 3.3 (= logic 1), other to ground (= logic 0 ) with resistors between. I am looking forward to have hardware rotation too (I don't want to use framebuffer rotation, because it needs two frame buffers, and that means slower system and used RAM), I think that permanent resistor to 3.3 and to ground have to be cut, and similar resistors soldered on U/D L/R jumpers, then you could use GPIO to rotate screen.... just every rotation needs different screen configuration :/

[essebie]

It is so because LCD panels (look to schematics) have pins of lines U/D L/R is disconnected from GPIO with open jumpers, and instead one line is connected to 3.3 (= logic 1), other to ground (= logic 0 ) with resistors between.

The hardware rotation is a purpose of the LCD controller, not of A20 board.
If you see the datasheet  of the display, here:
https://www.olimex.com/Products/OLinuXino/A13/A13-LCD10TS/resources/F101TT50_1_release.pdf
at pag. 17 explains the UPDN and SHLR control function.
This simply doesn't work, with any combination of logic levels at U/D & L/R, I see always the same image.

If I short circuit the resistors, I symply short the pullup or pulldown resistor and change the logic level of pin.

As you can see here:
https://dl.dropboxusercontent.com/u/2370367/A13-LCD10TS_sch.pdf
the schematic provides U/D and L/R wired links directly to display, not the GPIO.

I am looking forward to have hardware rotation too (I don't want to use framebuffer rotation, because it needs two frame buffers, and that means slower system and used RAM)

I also would prefer not to use the framebuffer rotation, but I fear that is the only way.

Stefano

[essebie]

I also would prefer not to use the framebuffer rotation, but I fear that is the only way.

Maybe is not the only way.

In the datasheet od A20, here:

https://github.com/OLIMEX/OLINUXINO/blob/master/HARDWARE/A20-PDFs/A20%20User%20Manual%202013-03-22.pdf?raw=true

At pag.330 is described a register for a harware rotation.
"Offset: iDMA0:0x50   IDMA_ROTMIRCTL
Rotation and mirroring control.
0:normal
1:X
2:Y
3:XY
4:A
5:AX
6:AY
7:AXY
Other: reserved
"

Unfortunatly the Fex file don't implement any feature to change this point, or is not explained correctly, and so is a problem change this configuration, also if is possible make some attempts directly on register with a poke.

Stefano

[essebie]

I have to apologize with all people, but the lack of rotation hw of LCD was due to my mistake.

After a recompilation of QT to permit a software screen rotation, yesterday came here a friend that don't believe at a lack of the LCD hardware controller..

In effect, due to my not young age, I misread the silkscreen and I wrong to short-circuit the R24.
When he does a correct short-circuit over R24, the display suddenly shows a image upside-down.

I 've spent a lot of time for nothing, I'm sorry

Stefano

[granite_crusher]

essebie,

when you got image upside down, does it had misalignment? I was wondering if you rotate 180 degrees does front porch gets to back porch, and back porch as front porch?

granite

[essebie]

when you got image upside down, does it had misalignment? I was wondering if you rotate 180 degrees does front porch gets to back porch, and back porch as front porch?

The image is upside-down of 180°, but you need to short-circuit R24 & R31.

Here the schematic, pay attention with the silkscreen on pcb to find R24

https://dl.dropboxusercontent.com/u/2370367/A13-LCD10TS_sch.pdf

Stefano

[granite_crusher]

essebie,

I understand part of short circuiting ( R24 R31). But my question is about if image looks the same rotated because theoretically 180 reversed image should be misaligned(to the left or right, depending on LCD spec) as back and front porch (left and right virtual section of lcd) should swich places. So does images look identical (not counting that it is reversed)?

granite

[essebie]

granite,

the image is exactly the same, with a 180° rotation and the advantage that the view angle now is ok for a frontal seeing.

Stefano